The present invention relates generally to the implant of prosthetic joints and pertains, more specifically, to the preparation of the distal femur for the implantation of a femoral knee prosthesis, utilizing a femoral cutting guide to assist in establishing the surfaces necessary for locating and securing the prosthesis in place on the femur. More particularly, it relates to a cutting guide which is light weight, strong and easy to manufacture.
The implant of a prosthetic knee joint requires that the distal femur be prepared to receive the femoral component of the knee prosthesis by cutting the bone of the femur to establish accurately located surfaces. Upon implantation, the femoral component will rest on these surfaces. As used herein, when referring to bones or other parts of the body, the term “proximal” means closer to the heart and the term “distal” means more distant from the heart. The term “inferior” means toward the feet and the term “superior” means towards the head. The term “anterior” means towards the front part of the body or the face and the term “posterior” means towards the back of the body. The term “medial” means toward the midline of the body and the term “lateral” means away from the midline of the body.
Various resection guides are available to the surgeon for assisting in guiding a saw blade to make the femoral cuts which establish the desired surfaces. These guides usually have guide surfaces for making four resections and are located and secured on the distal femur, upon an already resected transverse surface on the distal femur. Typically, surfaces are provided for guiding the saw blade during the execution of an axially directed anterior femoral cut, an axially directed posterior femoral cut, an anterior chamfer cut and a posterior chamfer cut, all specifically related to the size of the femoral knee prosthesis to be implanted and to the position and orientation of the femoral knee prosthesis on the distal femur. This type of cutting block is known as a four in one cutting block. Such blocks are shown in U.S. Pat. Nos. 4,892,093, 5,012,909, 5,364,401, 5,683,397 and 6,258,095. The appropriate location of a femoral cutting guide, then, generally requires the use of well known instruments and alignment techniques to determine the size of the femoral knee prosthesis which will be implanted at an implant site in a particular recipient, and to locate the corresponding femoral cutting guide appropriately on the transverse distal femoral surface for proper placement of the femoral knee prosthesis upon implant at the implant site.